Liquid crystal display

ABSTRACT

The present invention relates to a liquid crystal display (LCD) and a method of manufacturing the same. In the present invention, a wire grid polarizing pattern is formed on at least one of thin film transistor and color filter substrates in a manufacturing process thereof. According to the present invention, the thickness of an LCD panel can be reduced as compared with a method of attaching an existing polarizer to an LCD panel, and the wire grid polarizing pattern can be built in an LCD panel without increasing the number of masking processes.

REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean patent application No.10-2006-0104251 filed in the Korean Intellectual Property Office on Oct.26, 2006

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a liquid crystal display (LCD), andmore particularly, to an LCD in which a wire grid polarizer is formed onat least one of a thin film transistor substrate and a color filtersubstrate.

2. Description of the Prior Art

A liquid crystal display (LCD) comprises a thin film transistor (TFT)substrate with a pixel electrode formed thereon, a color filtersubstrate with a common electrode formed thereon, and a liquid crystallayer interposed between the two substrates. The LCD displays an imagein such a manner that liquid crystal molecules are rearranged byapplying a data voltage between the pixel and common electrodes to varythe amount of light transmitted through the liquid crystal layer. Sincesuch an LCD is not self-luminescent, an image is displayed by means oflight incident from the outside. To this end, a backlight unit ismounted to a rear surface of the LCD.

Light radiated from the backlight unit is not incident directly onto anLCD panel but incident with a polarization characteristic providedthrough a polarizer. Thus, an LCD displays an image using the opticalanisotropy of liquid crystal molecules and the polarizationcharacteristic of a polarizer.

An existing method of mounting a polarizer on an LCD panel includesattaching a polymer-type polarizer to the outside of an LCD panel. In arepresentative method, iodine molecules are chemically bonded on apolyvinylalcohol (PVA) base film in a predetermined direction through awet stretching method to impart the polarization characteristic. Whilesuch a polarizer has a superior polarization characteristic, itsmanufacture requires an additional process besides those involved inmanufacturing the LCD thereby increasing manufacturing cost.

Further, the existing attachable polarizer cannot provide polarizationfor each pixel of an LCD panel because the polarization characteristicare obtained by chemically bonding iodine molecules on thepolyvinylalcohol (PVA) base film in a predetermined direction throughwet stretching—resulting in the iodine molecules having a directionalproperty throughout the entire film. Thus, polarization cannot beindividually provided for each pixel of an LCD.

Further, since an attachable polarizer requires the use of an adhesiveagent, the thickness of the LCD panel is increased due to thethicknesses of the adhesive agent.

Unlike the aforementioned polymer type polarizer, a small-sized wiregrid polarizer has been developed and applied to products such asprojectors. In the wire grid polarizer, a stripe pattern with a linewidth and interval smaller than the wavelength of red, green or bluelight is formed on a base substrate. The wire grid polarizer is formedof a metal such as Al through a thin film machining method. That is, awire grid polarizing pattern is formed with a line width and interval of50 to 200 nm smaller than the blue light region that is the minimumoptical wavelength of visual light. In an LCD, light incident on thewire grid polarizing pattern formed in such a manner from a backlightunit, the light advances while vibrating in horizontal and verticaldirections with respect to its direction of advance. For this reason,only the light incident while vibrating in parallel with the spacesbetween regions in which the wire grid polarizing pattern is formedpasses through. A wire grid polarizer is a structure in which themetal-based wire grid polarizing pattern is formed in such a manner.

If such a wire grid polarizer is formed of a metallic material such asAl with optically high reflectivity, the light incident from a backlightunit while vibrating in a vertical direction with respect to the spacesbetween the regions in which the wire grid polarizing pattern is formeddoes not pass through and is reflected back to the backlight unit. Thus,if a phase transition layer with reflectivity different from the wiregrid polarizer, e.g., an anti-reflective layer, is formed under the wiregrid polarizer, a phase shift occurs in the phase transition layer andthe light is again incident to the wire grid polarizer, whereby anadditional polarization occurs.

The wire grid polarizer has the same effect as a dual brightnessenhancement film (DBEF) in which light recycling described abovecontinuously occurs, so that polarization transmittance is enhanced.Since the light recycling can be obtained without using the complicatedDBEF but by using a simple anti-reflective structure, a low-pricedpolarizer with high polarization can be manufactured.

However, the wire grid polarizer should be attached to the outside of anLCD panel like the existing polymer type polarizer after beingmanufactured through an additional manufacturing process. Therefore,such a wire grid polarizer is more expensive than a film attachablepolarizer in view of costs and the number of the entire processes.

SUMMARY OF THE INVENTION

According to one aspect of present invention a liquid crystal display(LCD) having a wire grid polarizer is formed when manufacturing the LCDpanel, whereby the thickness of the LCD panel is reduced as comparedwith an attachable polarizer and the cost and the number of processes ofthe LCD panel can be reduced.

According to an aspect of the present invention an LCD, comprises upperand lower substrates with predetermined element layers respectivelyformed thereon; and a liquid crystal layer interposed between the upperand lower substrates, wherein a wire grid polarizing pattern with apredetermined line width and interval is formed on at least one of theupper and lower substrates.

The wire grid polarizing pattern may be formed on a surface of each ofthe upper and lower substrates, or on the same plane as the elementlayer of the upper or lower substrate.

The LCD may further comprise a light conversion layer formed under thewire grid polarizing pattern.

According to another aspect of the present invention, there is providedan LCD comprising a thin film transistor (TFT) substrate having a gateline extending in one direction on a first substrate, a data lineextending in a direction perpendicular to the gate line and a pixelelectrode at a pixel region defined by the gate and data lines; and acolor filter substrate having a black matrix formed to correspond to aregion except the pixel region, a color filter formed corresponding tothe pixel region and a common electrode, wherein a wire grid polarizingpattern with a predetermined line width and interval is formed on atleast one substrate of the TFT and color filter substrates.

The wire grid polarizing pattern may be formed of a reflection material.

The wire grid polarizing pattern may be formed under the gate line, onthe same plane as the gate line, or on the same plane as the data line.

The wire grid polarizing pattern may be primarily formed under the gateline and secondarily formed on the same plane as the gate line.

The wire grid polarizing pattern may be primarily formed under the gateline and secondarily formed on the same plane as the data line.

The wire grid polarizing pattern may be primarily formed on the sameplane as the gate line and secondarily formed on the same plane as thedata line.

The secondarily formed wire grid polarizing pattern may be formed on aspace between regions in which the primarily formed wire grid polarizingpattern is formed.

The LCD wire grid polarizing pattern may be formed under the blackmatrix or on the same plane as the black matrix.

The wire grid polarizing pattern may be primarily formed under the blackmatrix and secondarily formed on the same plane as the black matrix.

The secondarily formed wire grid polarizing pattern may be formed on aspace between regions in which the primarily formed wire grid polarizingpattern is formed.

The LCD may further comprise a light conversion layer formed under thewire grid polarizing pattern. Here, the light conversion layer is formedon a predetermined substrate or thin film and attached to a bottomsurface of at least one of the first and second substrates, or on abottom surface of at least one of the first and second substrates bydepositing a predetermined film thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become apparent from the following description ofpreferred embodiments given in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a plan view schematically showing a liquid crystal display(LCD) panel according to the present invention;

FIG. 2 is a sectional view taken along line I-I′ in FIG. 1;

FIG. 3 is a sectional view taken along line II-II′ in FIG. 1;

FIGS. 4A to 4F are sectional views sequentially illustrating a method ofmanufacturing a thin film transistor (TFT) substrate with a first wiregrid polarizing pattern formed thereon according to a first embodimentof the present invention;

FIGS. 5A and 5B are sectional views sequentially illustrating a methodof manufacturing a TFT substrate with a first wire grid polarizingpattern formed thereon according to a second embodiment of the presentinvention;

FIGS. 6A to 6C are sectional views sequentially illustrating a method ofmanufacturing a TFT substrate with a first wire grid polarizing patternformed thereon according to a third embodiment of the present invention;

FIGS. 7A to 7C are sectional views sequentially illustrating a method ofmanufacturing a TFT substrate with a first wire grid polarizing patternformed thereon according to a fourth embodiment of the presentinvention;

FIGS. 8A to 8D are sectional views sequentially illustrating a method ofmanufacturing a TFT substrate with a first wire grid polarizing patternformed thereon according to a fifth embodiment of the present invention;

FIGS. 9A to 9D are sectional views sequentially illustrating a method ofmanufacturing a TFT substrate with a first wire grid polarizing patternformed thereon according to a sixth embodiment of the present invention;

FIGS. 10A to 10C are sectional views sequentially illustrating a methodof manufacturing a color filter substrate with a second wire gridpolarizing pattern formed thereon according to a first embodiment of thepresent invention;

FIGS. 11A and 11B are sectional views sequentially illustrating a methodof manufacturing a color filter substrate with a second wire gridpolarizing pattern formed thereon according to a second embodiment ofthe present invention; and

FIGS. 12A to 12C are sectional views sequentially illustrating a methodof manufacturing a color filter substrate with a second wire gridpolarizing pattern formed thereon according to a third embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the drawings, the thicknesses of layers and regions are exaggeratedfor clarity thereof, and like reference numerals are used to designatelike elements throughout the specification and drawings. Further, theexpression that an element such as a layer, region, substrate or plateis placed on or above another element includes not only a case where theelement is placed directly on or just above the other element but also acase where a further element is interposed between the element and theother element.

FIG. 1 is a plan view schematically showing a liquid crystal display(LCD) panel according to the present invention, FIG. 2 is a sectionalview taken along line I-I′ of the LCD panel in FIG. 1, and FIG. 3 is asectional view taken along line II-II′ in FIG. 1.

Referring to FIGS. 1 to 3, an LCD panel 300 includes a thin filmtransistor (TFT) substrate 100 and a color filter substrate 200 facingeach other, and a liquid crystal layer (not shown) interposedtherebetween. Further, the LCD panel 300 further includes at least oneof a first wire grid polarizing pattern 400 formed in one direction onan entire surface or pixel regions of the TFT substrate 100, and asecond wire grid polarizing pattern 500 formed in a direction verticalto the first wire grid polarizing pattern 400 on an entire surface ofthe color filter substrate 200 or regions thereof corresponding to thepixel regions of the TFT substrate 100.

The TFT substrate 100 includes a plurality of gate lines 121 extendingin one direction on a first insulation substrate 110; a plurality ofdata lines 141 intersecting the gate lines 121; pixel electrodes 151formed at the pixel regions defined by the gate and data lines 121 and141; and TFTs 125 connected to the gate and data lines 121 and 141 andthe pixel electrodes 151. Further, the TFT substrate 100 furtherincludes the first wire grid polarizing pattern 400 formed in the onedirection to have a predetermined width and interval in the pixelregions.

The gate line 121 mainly extends in an abscissa direction, and a portionof the gate line 121 protrudes in an ordinate direction to form a gateelectrode 122.

The data line 141 extends in one direction to perpendicularly intersectthe gate line 121, and a portion of the data line 141 protrudes to forma source electrode 142. Further, a drain electrode 143 is formed to bespaced apart from the source electrode 142 at a predetermined intervalwhen the data line 141 is formed.

Preferably, the gate line 121 is formed of any of Al, Nd, Ag, Cr, Ti, Taand Mo, or an alloy thereof. Further, the gate line 121 may be formed innot only a single layer but also a multi-layer including a plurality ofmetal layers. That is, the gate line 121 may be formed in a double-layerincluding a metal layer such as Cr, Ti, Ta or Mo with a superiorphysical and chemical characteristics and an Al- or Ag-based metal layerwith low specific resistance. Further, the aforementioned data line 141,source electrode 142 and drain electrode 143 may also be formed of theaforementioned metal and in a multi-layer.

The TFT 125 allows a pixel signal supplied to the data line 141 to becharged into the pixel electrode 151 in response to a signal supplied tothe gate line 121. Thus, the TFT 125 includes the gate electrode 122connected to the gate line 121; the source electrode 142 connected tothe data line 141; the drain electrode 143 connected to the pixelelectrode 151; a gate insulation film 131 and an active layer 132sequentially formed between the gate electrode 122 and the source anddrain electrodes 142 and 143; and an ohmic contact layer 133 formed onat least a portion of the active layer 132. At this time, the ohmiccontact layer 133 may be formed on the active layer 132 except a channelportion.

A protection film 144 is formed on the gate and data lines 121 and 141and the TFT 125. The protection film 144 may be formed of an inorganicmaterial such as silicone nitride or silicone oxide, and also be formedof an organic insulation film with a low permittivity. It will beapparent that the protection film 144 may be formed in a double-layerincluding inorganic and organic insulation films.

The pixel electrodes 151 are formed on the substrate 110 in the pixelregions defined by the gate and data lines 121 and 141 and connected tothe drain electrodes 143.

The first wire grid polarizing pattern 400 is formed on the entiresurface or the pixel regions of the TFT 100, and may be formed in anabscissa or ordinate direction or an inclined direction at apredetermined angle with respect to the gate line 121. As shown in thefigures, the first wire grid polarizing pattern 400 may be formed on thesubstrate 110 before the gate lines 121 are formed. In addition, thefirst wire grid polarizing pattern 400 may be formed simultaneously withthe gate lines 121 or the data lines 141. Further, the first wire gridpolarizing pattern 400 may be primarily formed before the gate lines 121are formed, and secondarily formed simultaneously with the gate lines121. Alternatively, the first wire grid polarizing pattern 400 may beprimarily formed before the data lines 141 are formed, and secondarilyformed simultaneously with the data lines 141. Furthermore, the firstwire grid polarizing pattern 400 may be primarily formed simultaneouslywith the gate lines 121, and secondarily formed simultaneously with thedata lines 141. When the first wire grid polarizing pattern 400 isformed twice, it is preferred that the secondarily formed first wiregrid polarizing pattern be positioned in spaces between regions in whichthe primarily formed first wire grid polarizing pattern is formed. Inthis case, it is preferred that the spaces between the regions in whichthe primarily formed first wire grid polarizing pattern is formed bewider than the line width of the secondarily formed first wire gridpolarizing pattern, so that light can easily pass through. That is, thespaces between the regions in which the primarily formed first wire gridpolarizing pattern is formed are set to be about twice a predeterminedwidth and the secondarily formed first wire grid polarizing pattern ispreferably set to have the same size as the primarily formed first wiregrid polarizing pattern, so that the secondarily formed first wire gridpolarizing pattern is positioned in the spaces between the regions inwhich the primarily formed first wire grid polarizing pattern is formed.

A storage line (not shown) may be formed to allow a liquid crystalvoltage applied to the liquid crystal layer (not shown) interposedbetween the TFT and color filter substrates 100 and 200 to be stablymaintained. For example, the storage line may be formed in the directionparallel with the gate lines 121 when the gate lines 121 are formed.

The color filter substrate 200 includes a black matrix 221, colorfilters 231, an overcoat film 241 and a common electrode 251, which areformed on a second insulation substrate 210. Further, the color filtersubstrate 200 further includes the second wire grid polarizing pattern500 formed on the entire surface of the color filter substrate 200 or inthe regions thereof corresponding to the pixel regions of the TFTsubstrate 100. Preferably, the second wire grid polarizing pattern 500is formed in the direction perpendicular to the first wire gridpolarizing pattern 400 in regions corresponding to the regions in whichthe first wire grid polarizing pattern 400 is formed.

The black matrix 221 is formed in regions other than the pixel regions,and prevents light leakage which would interfere with adjacent pixelregions. That is, the black matrix 221 has openings through which theregions in which the pixel electrodes 151 are formed.

The color filters 231 are formed such that red, green and blue filtersare repeated with the black matrix 221 being as boundaries. The colorfilter 231 serves to provide color to light emitted from a light sourceand then passing through the liquid crystal layer (not shown). The colorfilter 231 may be formed of a photosensitive organic material.

The overcoat film 241 is formed on the color filters 221 and the blackmatrix 221 uncovered with the color filters 221. The overcoat film 241serves to protect the color filters 231 and insulate between upper andlower conductive layers while flattening the color filters 231. Further,the overcoat film 241 may be formed of an acryl based epoxy material.

The common electrode 251 is formed on the overcoat film 241. The commonelectrode 251 is made of a transparent conductive material such as ITO(Indium Tin Oxide) or IZO (Indium Zinc Oxide). The common electrode 251supplies voltage to the liquid crystal layer (not shown) together withthe pixel electrode 151 of the TFT transistor 100.

Preferably, the second wire grid polarizing pattern 500 is formed in adirection perpendicular to the first wire grid polarizing pattern 400 onthe entire surface of the color filter substrate 200 or in the regionsthereof corresponding to the pixel regions of the TFT substrate 100,i.e., the regions in which the color filters are formed. Further, thesecond wire grid polarizing pattern 500 may be formed before the blackmatrix 221 is formed or simultaneously with the black matrix 221. Thesecond wire grid polarizing pattern 500 may be primarily formed beforethe black matrix 221 is formed and then secondarily formedsimultaneously with the black matrix 221. If the second wire gridpolarizing pattern 500 is formed twice, it is preferred that thesecondarily formed second wire grid polarizing pattern be positioned inspaces between regions in which the primarily formed second wire gridpolarizing pattern is formed. It is preferred that the spaces betweenthe regions in which the primarily formed second wire grid polarizingpattern is formed be wider than the line width of the secondarily formedsecond wire grid polarizing pattern, so that light can easily passthrough. That is, the spaces between the regions in which the primarilyformed second wire grid polarizing pattern is formed is set to be twicewider than a desired width and the secondarily formed second wire gridpolarizing pattern is preferably set to have the same size as theprimarily formed second wire grid polarizing pattern, so that thesecondarily formed second wire grid polarizing pattern is positioned onthe spaces between the regions in which the primarily formed second wiregrid polarizing pattern is formed.

Although the first wire grid polarizing pattern 400 has been describedas formed on the TFT substrate 100 and the second wire grid polarizingpattern 500 is formed on the color filter substrate 200, the presentinvention is not limited thereto. That is, any one of the first andsecond wire grid polarizing patterns 400 and 500 may be formed. Further,as shown in FIG. 1, light conversion layers 160 for allowing lightreflected from the wire grid polarizing pattern to be incident againupon the wire grid polarizing pattern may be further formed under theTFT and color filter substrates 100 and 200. The light conversion layers160 may be formed by attaching or depositing a predetermined film.

As described above, the wire grid polarizing pattern is formed on atleast one of the TFT and color filter substrates in the presentembodiment. Since a recycling structure is applied to the wire gridpolarizing pattern in view of a polarization principle, the apertureratio of the LCD panel is not reduced although the wire grid polarizingpattern is formed in the pixel regions of the TFT substrate. That is,where light is incident to the wire grid polarizing pattern with acertain polarization angle, the light vibrating in a horizontaldirection to the wire grid polarizing pattern is transmitted through thespaces between the regions in which the wire grid polarizing pattern isformed. However, the light vibrating in the perpendicular direction doesnot pass through the spaces between the regions in which the wire gridpolarizing pattern is formed, but is reflected. Thus, the light isreflected on the light conversion layer formed under the substrate andthen incident again on the wire grid polarizing pattern. Since thepolarized light is entirely induced due to the light recycling repeatedin such a manner, the aperture ratio is not reduced although the wiregrid polarizing pattern made of a reflective metal component is formedthroughout the pixel regions of the LCD panel.

Hereinafter, a variety of embodiments of forming the first wire gridpolarizing pattern 400 on the TFT substrate 100 according to the presentinvention will be described.

FIGS. 4A to 4F are sectional views sequentially illustrating a method ofmanufacturing a TFT substrate with a first wire grid polarizing patternformed thereon according to a first embodiment of the present invention.

Referring to FIG. 4A, a first conductive layer is formed on a substrate110, and the first conductive layer is then patterned through a photoand etching process using a first mask to form a first wire gridpolarizing pattern 400 with a predetermined line width and interval.Here, a metallic or non-metallic material including Al or otherreflection materials is used to form the first conductive layer for thefirst wire grid polarizing pattern 400. Further, the first wire gridpolarizing pattern 400 is formed on an entire surface of the substrate110 to be aligned in one direction. For example, the first wire gridpolarizing pattern 400 is formed in a direction parallel with orperpendicular to a gate line 121 or in an inclined direction at apredetermined angle with respect to the gate line 121. Further, aninsulation film 120 is formed on top of the substrate 120 with the firstwire grid polarizing pattern 400 formed thereon. For example, theinsulation film 120 is formed of a silicone oxide film.

Referring to FIG. 4B, a second conductive layer is formed on top of thesubstrate 110 with the first wire grid polarizing pattern 400 and theinsulation film 120 formed thereon, and then patterned through a photoand etching process using a second mask. Accordingly, the gate line 121including a gate electrode 122 is formed. Further, a gate insulationfilm 131 is formed on top of the entire surface of the substrate 110.Here, the gate insulation film 131 is formed of an inorganic insulationfilm.

Referring to FIG. 4C, an active layer 132 and an ohmic contact layer 133are sequentially formed on a top of the entire structure. Here, anamorphous silicone layer is used to form the active layer 132, and asilicide or amorphous silicone layer doped with highly concentratedN-type impurities is used to form the ohmic contact layer 133.Thereafter, the active layer 132 and the ohmic contact layer 133 arepatterned through a photo and etching process using a third mask suchthat they overlap with the gate electrode 122.

Referring to FIG. 4D, a third conductive layer is formed on top of theentire structure and then patterned through a photo and etching processusing a fourth mask. Accordingly, a data line 141 as well as source anddrain electrodes 142 and 143 is formed. At this time, the source anddrain electrodes 142 and 143 are formed to be spaced apart from eachother at a predetermined interval, and the active layer exposed by thesource and drain electrodes 142 and 143 becomes a channel region. Here,it is preferred that a single or multi metal layer be used to form thethird conductive layer. Further, the same material as the secondconductive layer for forming the gate line 121 may be used to form thethird conductive layer.

Referring to FIG. 4E, a protection film 144 is formed on top of theentire structure. The protection film 144 may be formed of an inorganicinsulation film such as a silicone oxide film or nitride oxide film, oran organic insulation film such as BCB (Benzocyclobutane) or acrylresin. Further, the protection film 144 may be formed by laminating theorganic and inorganic insulation films. Thereafter, a predeterminedregion of the protection film 144 is etched through a photo and etchingprocess using a fifth mask to form a contact hole 161 exposing the drainelectrode 143.

Referring to FIG. 4F, a fourth conductive layer is formed on top of theentire structure and then patterned through a photo and etching processusing a sixth mask to form a pixel electrode 151. Here, it is preferredthat a transparent conductive layer comprising indium tin oxide (ITO) orindium zinc oxide (IZO) be used to form the fourth conductive layer.

Although a method of manufacturing the TFT substrate 100 using sixsheets of masks has been illustrated in the above, the present inventionis not limited thereto but may be applied to various mask processes.

In the first embodiment of the present invention described above, thefirst wire grid polarizing pattern 400 is first formed on top of thesubstrate 110, and a process of forming the gate and data lines 121 and141 is then performed. In this case, although the process of forming thefirst wire grid polarizing pattern 400 on top of the substrate 110 isadded, the first wire grid polarizing pattern 400 is formed directly ona surface of the substrate 110. For this reason, the first embodiment ofthe present invention is a stable method since the process failures dueto a step do not occur in a process, as compared with a case where thegate or data line 121 or 141 is formed and the first wire gridpolarizing pattern 400 is then formed.

Hereinafter, a method of manufacturing a TFT substrate with a first wiregrid polarizing pattern formed thereon according to other embodiments ofthe present invention will be described. Descriptions overlapping withthe first embodiment of the present invention will be omitted, and onlythose features that are different from the first embodiment of thepresent invention will be described.

FIGS. 5A and 5B are sectional views sequentially illustrating a methodof manufacturing a TFT substrate with a first wire grid polarizingpattern formed thereon according to a second embodiment of the presentinvention, in which the first wire grid polarizing pattern issimultaneously formed when a gate line is formed. Accordingly, thenumber of processes can be reduced as compared with the firstembodiment.

Referring to FIG. 5A, a first conductive layer is formed on top of asubstrate 110 and then patterned through a photo and etching processusing a predetermined mask. Accordingly, a gate line 121 as well as agate electrode 122 is formed, and a first wire grid polarizing pattern400 is simultaneously formed. Here, the gate line 121 is formed toextend in one direction, e.g., in an abscissa direction. Further, thefirst wire grid polarizing pattern 400 is formed to be aligned in onedirection in pixel regions, e.g., in a direction parallel with orperpendicular to the gate line or in an inclined direction at apredetermined angle with respect to the gate line 121. Furthermore, agate insulation film 131 is formed on top of the entire structure.

Referring to FIG. 5B, a data line 141 is formed, and source and drainelectrodes 142 and 143 are simultaneously formed. A pixel electrode 151in contact with the drain electrode 143 is formed in the pixel region.

FIGS. 6A to 6C are sectional views sequentially illustrating a method ofmanufacturing a TFT substrate with a first wire grid polarizing patternformed thereon according to a third embodiment of the present invention,in which the first wire grid polarizing pattern is simultaneously formedwhen a data line is formed. Accordingly, the number of processes can bereduced as compared with the first embodiment.

Referring to FIG. 6A, a first conductive layer is formed on top of asubstrate 110 and then patterned through a photo and etching processusing a predetermined mask so as to form a gate line 121 as well as agate electrode 122. Further, a gate insulation film 131, an active layer132 and an ohmic contact layer 133 are formed, and then the active layer132 and the ohmic contact layer 133 are patterned to overlap with thegate electrode 121.

Referring to FIG. 6B, a second conductive layer is formed on top of theentire structure and then patterned through a photo and etching processusing a predetermined mask. Accordingly, a data line 141 as well assource and drain electrodes 142 and 143 is formed, and a first wire gridpolarizing pattern 400 is simultaneously formed. Here, the data line 141is formed to extend in a direction perpendicular to the gate line 121.Further, the first wire grid polarizing pattern 400 is formed to bealigned in one direction in a pixel region defined by the gate and datalines 121 and 141, e.g., in a direction parallel with or perpendicularto the gate line 121 or in an inclined direction at a predeterminedangle with respect to the gate line 121.

Referring to FIG. 6C, a protection film 144 is formed on top of theentire structure, and a contact hole 161 exposing a predetermined regionof the drain electrode 143 is then formed through a photo and etchingprocess using a predetermined mask. Then, a pixel electrode 151 incontact with the drain electrode 143 is formed in the pixel region.

According to the aforementioned second and third embodiments, in a casewhere the first wire grid polarizing pattern 400 is formedsimultaneously with the gate or data line 121 or 141, an additionalprocess for forming the first wire grid polarizing pattern 400 is notadded. Since processes of patterning the first wire grid polarizingpattern 400 and forming an insulation film 120 are omitted, as comparedwith the first embodiment, the number of processes can be reduced.

In the aforementioned method of manufacturing a TFT substrate with thefirst wire grid polarizing pattern formed thereon according to the firstto third embodiments, the first wire grid polarizing pattern is formedwith a line width and interval of about 50 to 200 nm. However, since theline width and interval of such a wire grid polarizing pattern is asnarrow as a nano scale, it is considerably difficult to form the wiregrid polarizing pattern. Accordingly, the first wire grid polarizingpattern is primarily and secondarily formed in a double layer, so thatthe line width and interval of the first wire grid polarizing patterncan be more precisely controlled and the process yield of manufacturingthe first wire grid polarizing pattern can be enhanced. Hereinafter,such embodiments will be described in detail. Descriptions overlappingwith the aforementioned embodiments will also be omitted herein.

FIGS. 7A to 7C are sectional views sequentially illustrating a method ofmanufacturing a TFT substrate with a first wire grid polarizing patternformed thereon according to a fourth embodiment of the presentinvention, in which the first wire grid polarizing pattern is primarilyformed on top of a substrate before a gate line is formed, andsecondarily formed simultaneously with the gate line.

Referring to FIG. 7A, a first conductive layer is formed on top of asubstrate 110 and then patterned through a photo and etching processusing a predetermined mask so as to primarily form a first wire gridpolarizing pattern 400 a with a predetermined line width and interval.At this time, the interval between regions in which the primarily formedfirst wire grid polarizing pattern 400 a is formed should be wider thana finally desired interval. For example, the interval between theregions in which the first wire grid polarizing pattern 400 a is formedis twice or more than the finally desired interval. Further, aninsulation film 120 is formed on top of the substrate 110 with the firstwire grid polarizing pattern 400 a primarily formed thereon. Forexample, the insulation film 120 is formed of a silicone oxide film.

Referring to FIG. 7B, a second conductive layer is formed on top of thesubstrate 110 with the first wire grid polarizing pattern 400 a and theinsulation film 120 formed thereon and then patterned through a photoand etching process using a predetermined mask. Accordingly, a gate line121 as well as a gate electrode 122 is formed, and a first wire gridpolarizing pattern 400 b is secondarily formed at the same time. Here,the secondarily formed first wire grid polarizing pattern 400 b isformed in the same direction as the primarily formed first wire gridpolarizing pattern 400 a. Further, the secondarily formed first wiregrid polarizing pattern 400 b is formed on top of the insulation film120, and the secondarily formed first wire grid polarizing pattern 400 bis formed on the spaces between the regions in which the primarilyformed first wire grid polarizing pattern 400 a is formed. That is, theprimarily formed first wire grid polarizing pattern 400 a and thesecondarily formed first wire grid polarizing pattern 400 b formedthereon are alternately formed. Further, a gate insulation film 131 isformed on top of the entire structure.

Referring to FIG. 7C, a third conductive layer is formed, and source anddrain electrodes 142 and 143 are then formed simultaneously with a dataline 141 through a photo and etching process using a predetermined mask.Further, a protection film 144 is formed, and a pixel electrode 151 incontact with the drain electrode 143 is then formed.

FIGS. 8A to 8D are sectional views sequentially illustrating a method ofmanufacturing a TFT substrate with a first wire grid polarizing patternformed thereon according to a fifth embodiment of the present invention,in which the first wire grid polarizing pattern is primarily formed ontop of a substrate before a gate line is formed, and secondarily formedsimultaneously when a data line is formed.

Referring to FIG. 8A, a first conductive layer is formed on top of asubstrate 110 and then patterned through a photo and etching processusing a predetermined mask so as to primarily form a first wire gridpolarizing pattern 400 a with a predetermined line width and interval.At this time, the interval between regions in which the primarily formedfirst wire grid polarizing pattern 400 a is formed should be formedwider twice or more than a finally desired interval. Further, aninsulation film 120 is formed on top of the substrate 110 with the firstwire grid polarizing pattern 400 a primarily formed thereon. Forexample, the insulation film 120 is formed of a silicone oxide film.

Referring to FIG. 8B, a second conductive layer is formed on the topsurface of the substrate 110 and then patterned through a photo andetching process using a predetermined mask so as to form a gate line 121as well as a gate electrode 122. Further, an active layer 132 and anohmic contact layer 133 are formed to overlap with an gate insulationfilm 131 and the gate electrode 122.

Referring to FIG. 8C, a third conductive layer is formed on top of theentire structure and then patterned through a photo and etching processusing a predetermined mask. Accordingly, a data line 141 as well assource and drain electrodes 142 and 143 is formed, and a first wire gridpolarizing pattern 400 b is secondarily formed at the same time. Here,the secondarily formed first wire grid polarizing pattern 400 b isformed in the same direction as the primarily formed first wire gridpolarizing pattern 400 a. Further, the secondarily formed first wiregrid polarizing pattern 400 b is formed on the gate insulation film 131,and the secondarily formed first wire grid polarizing pattern 400 b isformed on spaces between the regions in which the primarily formed firstwire grid polarizing pattern 400 a is formed.

Referring to FIG. 8D, a protection film 144 is formed on the top surfaceof the entire structure, and a contact hole 161 exposing a predeterminedregion of the drain electrode 143 is then formed through a photo andetching process using a predetermined mask. Then, a pixel electrode 151contacted with the drain electrode 143 is formed in a pixel region.

FIGS. 9A to 9D are sectional views sequentially illustrating a method ofmanufacturing a TFT substrate with a first wire grid polarizing patternformed thereon according to a sixth embodiment of the present invention,in which the first wire grid polarizing pattern is primarily formedsimultaneously with a gate line, and secondarily formed simultaneouslywith a data line.

Referring to FIG. 9A, a first conductive layer is formed on top of asubstrate 110 and then patterned through a photo and etching processusing a predetermined mask. Accordingly, a gate line 121 as well as agate electrode 122 is formed, and a first wire grid polarizing pattern400 a is primarily formed at the same time. Here, the gate line 121 isformed in one direction, e.g., in an abscissa direction. Further, theinterval between regions in which the primarily formed first wire gridpolarizing pattern 400 a is formed is wider than a finally desiredinterval. Then, a gate insulation film 131 is formed on top of an entiresurface of the substrate 110 with the primarily formed first wire gridpolarizing pattern 400 a formed thereon.

Referring to FIG. 9B, an active layer 132 and an ohmic contact layer 133are formed on a top surface of an entire surface and then patterned tooverlap with the gate electrode 122 through a photo and etching processusing a predetermined mask.

Referring to FIG. 9C, a second conductive layer is formed on the topsurface of the entire structure and then patterned through a photo andetching process using a predetermined mask. Accordingly, a data line 141as well as source and drain electrodes 142 and 143 is formed, and at thesame time, a first wire grid polarizing pattern 400 b is secondarilyformed. Here, the secondarily formed first wire grid polarizing pattern400 b is formed in the same direction as the primarily formed first wiregrid polarizing pattern 400 a. Further, the secondarily formed firstwire grid polarizing pattern 400 b is formed on the gate insulation film131, and the secondarily formed first wire grid polarizing pattern 400 bis formed on spaces between regions in which the primarily formed firstwire grid polarizing pattern 400 a is formed.

Referring to FIG. 9D, a protection film 144 is formed on the top surfaceof the entire structure, and a contact hole 161 exposing a predeterminedregion of the drain electrode 143 is then formed through a photo andetching process using a predetermined mask. Then, a pixel electrode 151in contact with the drain electrode 143 is formed in a pixel region.

If the first wire grid polarizing pattern is formed in a multiple layerstructure having upper and lower layers as the aforementioned fourth tosixth embodiments, the line width and interval of the first wire gridpolarizing pattern can be precisely controlled and reduced as comparedwith a single layer structure. Therefore, light emitted from a backlightunit can be prevented from leaking in an outer portion of the first wiregrid polarizing pattern.

As described above, the embodiments of forming the first wire gridpolarizing pattern 400 on the TFT transistor substrate 100 have beendescribed. Hereinafter, embodiments of forming a second wire gridpolarizing pattern 500 on a color filter substrate 200 will bedescribed.

FIGS. 10A to 10C are sectional views sequentially illustrating a methodof manufacturing a TFT substrate with a second wire grid polarizingpattern formed thereon according to a first embodiment of the presentinvention, in which the second wire grid polarizing pattern is formed ontop of a substrate before the black matrix is formed.

Referring to FIG. 10A, a first conductive layer is formed on top of asubstrate 210 and then patterned through a photo and etching processusing a predetermined mask so as to form a second wire grid polarizingpattern 500 with a predetermined line width and interval. Here, ametallic or nonmetallic material including Al or other reflectionmaterials is used to form the first conductive layer for the second wiregrid polarizing pattern 500. Preferably, the second wire grid polarizingpattern 500 is formed on an entire surface of the substrate 210, andformed to be aligned in the direction perpendicular to the first wiregrid polarizing pattern 400. Further, an insulation film 220 is formedon top of the substrate 210 with the second wire grid polarizing pattern500 formed thereon. For example, the insulation film 220 is formed of asilicone oxide film.

Referring to FIG. 10B, a second conductive layer is formed on top of theentire surface of the substrate with the second wire grid polarizingpattern 500 and the insulation film 220 formed thereon and thenpatterned through a photo and etching process using a predetermined maskso as to form a black matrix 221. The second conductive layer forforming the black matrix 221 comprises Cr or CrO. Further, the blackmatrix 221 is formed at portions corresponding to a gate line 121 and adata line 141 and a TFT 125 of a TFT substrate 100.

Referring to FIG. 10C, red, green and blue resists are sequentiallyapplied on top of the substrate 210 with the black matrix 221 formedthereon and then patterned to form color filters 231 sequentiallyaligned in the black matrix. Further, an overcoat film 241 is formed ontop of the entire structure. The overcoat film 241 serves to not onlyprotect the color filters 231 while flattening the color filters 231 butalso electrically insulate the black matrix 221 and a common electrode251, which are formed of a conductive material. Further, the overcoatfilm 241 is formed of an acryl based epoxy material. Thereafter, atransparent conductive layer including an ITO or IZO film is formed ontop of the entire structure so as to form the common electrode 251.

In the foregoing embodiment, it has been described that the second wiregrid polarizing pattern 500 is formed on top of the substrate 210 beforethe black matrix 231 is formed. In this case, although a process offorming the second wire grid polarizing pattern 500 on top of thesubstrate 210 is added, the second wire grid polarizing pattern 500 isformed directly on top of the substrate 210. For this reason, processfailures due to the step do not occur. Therefore, the first embodimentof the present invention is a stable method as compared with a casewhere the second wire grid polarizing pattern 500 is formedsimultaneously with the black matrix.

Hereinafter, a method of manufacturing a color filter substrate with asecond wire grid polarizing pattern formed thereon according to otherembodiments of the present invention will be described. Descriptionsoverlapping with the first embodiment of the present invention will beomitted, and the descriptions different from the first embodiment of thepresent invention will be described in priority.

FIGS. 11A and 11B are sectional views sequentially illustrating a methodof manufacturing a TFT substrate with a second wire grid polarizingpattern formed thereon according to a second embodiment of the presentinvention, in which the second wire grid polarizing pattern is formedsimultaneously with a black matrix.

Referring to FIG. 11A, a conductive layer is formed on top of asubstrate 210 and then patterned through a photo and etching processusing a predetermined mask. Accordingly, a black matrix 221 is formed,and a second wire grid polarizing pattern 500 is simultaneously formed.Here, the conductive layer for forming the black matrix 221 and thesecond wire grid polarizing pattern 500 comprises Cr or CrO. Further,the black matrix 221 is formed at portions corresponding to a gate line121, a data line 141 and a TFT 125 of a TFT substrate 100, and thesecond wire grid polarizing pattern 500 is formed in the directionperpendicular to the first wire grid polarizing pattern 400 in a regioncorresponding thereto.

Referring to FIG. 11B, red, green and blue resists are sequentiallyapplied on top of the substrate 210 with the black matrix 221 and thesecond wire grid polarizing pattern 500 formed thereon, and thenpatterned to form color filters 231 sequentially aligned in the blackmatrix 221. Further, an overcoat film 241 is formed on top of the entirestructure, and a transparent conductive layer comprising an ITO or IZOfilm is then formed on top of the entire structure so as to form acommon electrode 251.

FIGS. 12A to 12C are sectional views sequentially illustrating a methodof manufacturing a TFT substrate with a second wire grid polarizingpattern formed thereon according to a third embodiment of the presentinvention, in which the second wire grid polarizing pattern is primarilyformed before a black matrix is formed, and secondarily formedsimultaneously with the black matrix.

Referring to FIG. 12A, a first conductive layer is formed on top of asubstrate 210 and then patterned through a photo and etching processusing a predetermined mask so as to primarily form a second wire gridpolarizing pattern 500 a with a predetermined line width and interval.At this time, the interval between regions in which the primarily formedsecond wire grid polarizing pattern 500 a is formed is wider than afinally desired interval. Further, an insulation film 220 is formed ontop of the substrate 210 with the second wire grid polarizing pattern500 a primarily formed thereon. For example, the insulation film 220 isformed of a silicone oxide film.

Referring to FIG. 12B, a second conductive layer is formed on a topsurface of the insulation film 220 and then patterned through a photoand etching process using a predetermined mask. Accordingly, a blackmatrix 221 is formed, and a second wire grid polarizing pattern 500 b issecondarily formed at the same time. Here, the conductive layer for theblack matrix 221 and the secondarily formed second wire grid polarizingpattern 500 b comprises Cr or CrO. Further, the secondarily formedsecond wire grid polarizing pattern 500 b is formed on top of theinsulation film 220, and the secondarily formed second wire gridpolarizing pattern 500 b is formed on spaces between the regions inwhich the primarily formed second wire grid polarizing pattern 500 a isformed.

Referring to FIG. 12C, red, green and blue resists are sequentiallyapplied on top of the substrate 210 with the black matrix 221 and thesecond wire grid polarizing pattern 500 formed thereon, and thenpatterned to form color filters 231 sequentially aligned in the blackmatrix 221. Further, an overcoat film 241 is formed on top of the entirestructure, and a transparent conductive layer comprising an ITO or IZOfilm is then formed on top of the entire structure so as to form acommon electrode 251.

In the aforementioned embodiments, an LCD has been described, in whichthe gate and data lines 121 and 141 and the pixel electrode 151 areformed on the TFT substrate 100, and the black matrix 221, the colorfilters 231 and the common electrode 251 are formed on the color filtersubstrate 200. However, the present invention is not limited thereto butmay be applied to both various liquid crystal cell structures andvarious pixel forms. For example, in a case where the black matrix 221is formed on top of the TFT substrate 100, the present invention can beapplied to all the methods of manufacturing LCD panels, including a casewhere the common electrode 251 is formed on the TFT substrate 100.

As described above, according to the present invention, a wire gridpolarizing pattern is formed on at least one substrate of TFT and colorfilter substrates. Accordingly, the thickness of an LCD panel can bereduced as compared with a method of attaching an existing polarizer tothe LCD panel. Further, a wire grid polarizing pattern is formedsimultaneously in a process of forming a structure of a TFT or colorfilter substrate, so that the wire grid polarizing pattern can be builtin an LCD panel without increasing the number of masking processes.

It will be apparent that those skilled in the art can make variousmodifications and changes thereto without, however, departing from thespirit and scope of the invention.

1. A liquid crystal display (LCD), comprising: a thin film transistor(TFT) substrate having a gate line extending in one direction on a firstsubstrate, a data line extending in a direction perpendicular to thegate line and a pixel electrode at a pixel region defined by the gateand data lines; and a color filter substrate having a black matrixformed to correspond to a region except the pixel region on a secondsubstrate, a color filter formed corresponding to the pixel region and acommon electrode, wherein a first wire grid polarizing pattern is formedbetween the gate line and the first substrate, and wherein a second wiregrid polarizing pattern is formed between the black matrix and thesecond substrate.
 2. The LCD as claimed in claim 1, wherein the first tothird wire grid polarizing pattern is formed of a reflection material.3. The LCD as claimed in claim 1, wherein a third wire grid polarizingpattern is formed on the same plane as the gate line.
 4. The LCD asclaimed in claim 3, wherein the third wire grid polarizing pattern isformed on a space between regions in which the first wire gridpolarizing pattern is formed.
 5. The LCD as claimed in claim 1, furthercomprising a light conversion layer formed under the at least one of theupper and lower substrates.
 6. The LCD as claimed in claim 1, wherein afourth wire grid polarizing pattern formed on the same plane as theblack matrix, wherein the fourth wire grid polarizing pattern is formedon a space between regions in which the second wire grid polarizingpattern is formed.
 7. A liquid crystal display (LCD), comprising: a thinfilm transistor (TFT) substrate having a gate line extending in onedirection on a first substrate, a data line extending in a directionperpendicular to the gate line and a pixel electrode at a pixel regiondefined by the gate and data lines; and a color filter substrate havinga black matrix formed to correspond to a region except the pixel region,a color filter formed corresponding to the pixel region and a commonelectrode, wherein a first wire grid polarizing pattern is formedbetween the gate line and the first substrate, wherein a second wiregrid polarizing pattern is formed on the color filter substrate, whereina third wire grid polarizing pattern is formed on the same plane as thegate line, and wherein the third wire grid polarizing pattern is formedon a space between regions in which the first wire grid polarizingpattern is formed.
 8. A liquid crystal display (LCD) comprising: a thinfilm transistor (TFT) substrate having a gate line extending in onedirection on a first substrate, a data line extending in a directionperpendicular to the gate line and a pixel electrode at a pixel regiondefined by the gate and data lines; and a color filter substrate havinga black matrix formed to correspond to a region except the pixel region,a color filter formed corresponding to the pixel region and a commonelectrode, wherein a first wire grid polarizing pattern is formedbetween the gate line and the first substrate, wherein a second wiregrid polarizing pattern is formed on the color filter substrate, andwherein a third wire grid polarizing pattern is formed on the same planeas the gate line.